Sorry guys but these are nothing more than your own opinions and not fact or in any manner what a dealer should do.
I service my own cars and have done for more years than I can remember, Three of these cars have 50,000 to 60,000 mile spark plug change intervals and I have waited until that time to remove the plugs.
I have been servicing cars for years and I know of no one among my many friends who service their own cars who would remove spark plugs on an annual basis on a modern car.
As always your cars and you do what you want but do not criticise servicing garages for carrying out work as advised by the manufacturer to their schedule.
Oh and over those years, I cleaned plugs at 12,000 miles on a car that were specified in those days to a 24,000 miles spark plug change.
I did not tighten one plug properly and it shot out the head after a few weeks.
I got away with just needing a helicoil in the head.
You may have your own opinions but in my experience with a modern car you can cause a problem with sorting something that is not broken!
